FERTlLIZlil^G SELF-STERILE GRAPES.* 



S. A. Beach. 



SUMMAEY. 



In Bulletin 157 were recorded the results of several seasons' 

 work in testing the self -fertility of the grape. Lists were given of 

 grapes which were perfectly self-fertile, partially self-fertile or 

 self-sterile and completely self-sterile. Many of onr cultivated 

 American grapes belong in the last two classes and require cross 

 pollination for formation of perfect bunches. The work of 1899 

 has been devoted to a study of the question whether some grapes 

 are better than others for fertilizing the self-sterile kinds. 



Prevention of accidental cross-pollination was secured by en- 

 closing in paper bags the selected bud clusters of both the variety 

 to be pollinated and that furnishing the pollen. Cross-pollina- 

 tion was effected by removing the pollinating cluster, when in 

 blossom, from the parent vine and enclosing it with the cluster to 

 be fertilized. The clusters were sometimes brushed together be- 

 fore enclosing, sometimes simply enclosed in the paper sacks and 

 shaken, to distribute the pollen. 



Twelve nearly or quite self-sterile varieties were treated with 

 pollen from one or more of twenty-four varieties ranging from 

 perfectly self-fertile to self-sterile. The results are given in the 

 body of the bulletin, both in detail and summarized. The use of 

 self-sterile varieties as poUinizers for other self-sterile varieties 

 resulted in failure. Self-sterile varieties fertilized with varieties 

 not strongly self-fertile produced clusters varying in compactness 

 about as did the bunches of the pollinating variety. Self -fertile 

 sorts, with rare exceptions, gave good results when used as fertil- 



• Reprint of Bulletin No. 169. 



